The Master Sword is a ship with which you can sail upstream and downstream through time's river... The port for that ship is in the Temple of Time...
While playing Ocarina of Time I started wondering about the time travel involved in it. For those of you who don't know, you start out as ten-year-old Link but after the first quarter of the game you travel seven years into the future. Later on, you get the ability to travel between both points in time.
The thing is, when you arrive in the future you've also physically aged seven years. So you've not so much travelled through time as slept through it. This makes some sense: when you pulled out the Master Sword, your spirit is sealed away for seven years until you're old enough to be able to weild it (young Link can barely reach to pull it out from the plinth in the first place!).
Anyway, you trundle along to Kakariko village, pick up the Hookshot, and then learn the Song of Storms. This one has always intrigued me. You learn the song from the windmill guy, who picked it up seven years ago when an Ocarina kid turned up and played a song which messed up the windmill. Ocarina kid? Well, it can't have been you, as you've never played this song before... or can it?
Potential paradoxes aside, at some point you'll head back to the Temple of Time. Here Sheik will appear and tell you that you can put the sword back in the pedastal, and by doing so you will travel back in time. This is where it gets weird. You never actually travelled forwards in time in the first place, but were just sealed away. And yet, returning the sword will not only take you back seven years, but when the blue light fades you're back in your ten-year-old body! This makes no sense by classical time travel theory, and no sense by the "sealed away" theory either.
The other puzzle, and what originally caused me to start writing this post, is *when* do you arrive? You don't return to the same point in time every time you use the sword, as things that you do as young Link don't get reverted. So the possibilities are that you return immediately (so that if someone was standing there in Past Hyrule, watching you, they'd see you grab the sword, a flash of blue light, and then you letting go of the sword), or that you travel back exactly seven years (so the watcher would see you disappear and reappear several days later)? I've never checked the in-game clock to work this one out.
You can also travel forwards in time again, though this is much more explainable: you get sealed away for seven years again. It's implied that you have no sense of what happens during these seven years - you blink, and you're a few feet taller.
Anyway, back to your younger self. After some more dungeon-crawling you end up back at the windmill again. Still no sign of that pesky Ocarina kid... but the only person in all of Past Hyrule that knows the Song of Storms is you, and so you play that song, teaching it to the windmill guy. The same windmill guy who seven years later teaches it back to you. It's a wonderful paradox, and just where did that song come from?
Just when you thought there was enough messing around with the time stream, you get the ending to the game (which I assume you all know, but stop reading now if you've somehow not finished it yet). The sages banish Ganon to the Sacred Realm, and seal him away for a long time. Future Hyrule is still a right mess: Hyrule Castle is a lava-filled crater, the town is a ruined shell, and monsters are roaming the land. So Zelda uses the Ocarina of Time to return you for the last time to Past Hyrule, though again I'm not sure when you arrive. You return to the Temple of Time, and the door is still open so Ganondorf can still waltz in and try to control the Triforce... except he's sealed away in the Sacred Realm. Even though that happened in the future. How does that work?
For added speculation, what happens to Future Hyrule? Remember, we've got a seven year period where for a large chunk of it Ganondorf ruled over all. This can't just disappear... can it? I remember an old TV cartoon where they sent someone to the past to defeat some evil. When their hero returned to the future and asked if he managed to stop the enemy, no-one knew who he was talking about. Does the same happen here: the Future Hyrule that we know morph into the new Future-without-Ganon Hyrule without anyone realising?
Did it really happen?